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No. 4 . 



Price, 25 cts. 


HOW TO INSTALL 


Ele&triq Bells, 
Annunqia tors, 

and Alarms. 


INCLUDING 

Batteries, Wires and Wiring, Circuits, Pushes, Bells, Burglar 
Alarms, High and Low Water Alarms, Fire Alarms, 
Thermostats, Annunciators, and the Location 


and Remedying of Troubles. 

By NORMAN H. SCHNEIDER. 























































































HOW TO INSTALL 

Electric Bells, Annunciators, 

and Alarms. 


INCLUDING 

Batteries, Wires and Wiring-, Circuits, Pushes, Bells, 
Burglar Alarms, High and Loxv Water Alarms, 
Fire Alarms, Thermostats, Annunciators, 
and the Location and Remedying 
of Troubles. 


BY 

NORMAN H. SCHNEIDER, 

\y 7 

Author of “The Study of Electricity for Beginners,” “Care and 
Handling of Electric Plants,” etc., etc. 


WITH FIFTY-NINE ORIGINAL ILLUSTRATIONS. 


> 

» 

> » 
> » 
!• > 

> 


NEW YORK 

SPON & CHAMBERLAIN, 123 Liberty St. 

LONDON 

E. & F. N. SPON, Limited, 57 Haymarket, S. W. 

1905 




LIBRARY Of CONGRESS 
fwo Copies rteceivbd 

FEB 21 1905 

* Copyriifiu tuiry 
odbts.'G, ttfaH 
CLASS GXj , xxc. Not 

/<? 3 -T# <? 

COPY Q. 



Copyright, 1904, at Washington, D. C. 
By Spon & Chamberlain 


Entered at Stationers’ Hall 






BURR PRINTING HOUSE 
NEW YORK 








PREFACE 


This book is intended for those who wish to 
install their own bells and annunciators or locate 
and remedy any trouble affecting such apparatus. 

In addition to electric bells and annunciators it 
deals with easily erected circuits for Burglar, Fire 
and Water level alarms. No apparatus has been 
described that is not readily procurable, and where 
criticism has been made of such, it is only intended 
to be of service to the reader. 

In many cases dry cells have been illustrated 
as being most easily handled; the reader may sub¬ 
stitute wet cells if desired. 






I 


CONTENTS 


Introduction 

Page 

Introduction. The principle of an electric bell. ix 

Chapter I 

The Leclanche cell—Polarization—Setting up—The 
dry cell—The gravity cell—Connecting up cells . 1 


Chapter II 

The single stroke bell—The shunt bell—The differen¬ 
tial bell—The continuous ring bell—The water¬ 
proof bell—Forms of gongs—The buzzer—Long 
distance bells—The relay—The push—Three point 
or double contact push—Floor push—Door pull 
—Indicating push.9 


Chapter III 

Bell wires—Joints—Running wires—How to put up a 
door bell—Combinations of bells, pushes and bat¬ 
teries—Faults in bells, faults in wiring—How to 
locate and remedy faults.23 





vi 


CONTENTS 


Chapter IV 

* Page 

Fire alarms—Thermostats—Metallic thermostats—Mer¬ 
cury thermostat—How to connect thermostats— 
Water level indicators—Burglar alarms—Open and 
closed circuit alarms—Window, door and shade 
springs—Alarm matting—Yale lock alarm—Doo 
trip alarm.40 


Chapter V 

The annunciator drop—The needle or arrow drop— 

The pendulum drop—Wiring up annunciators— 
Return or fire call systems—Double wire system— 
Western Electric single wire system .... 55 








LIST OF ILLUSTRATIONS 


FlG * Page 

1 Electric bell, push, and battery.x 

2 Leclanche cell.1 

3 Dry cell.4 

4 Gravity cell.5 

5 Vibrating bell.10 

6 Single stroke bell.10 

7 Shunt or short circuit bell.10 

8 Continuous ring bell.13 

9 Waterproof bell.14 

10 Dome gong. T 5 

11 Tea gong.15 

12 Cow gong.15 

13 Sleigh bell gong.15 

14 Spiral gong.15 

15 Relay and circuit.16 

16 Door push.19 

17 Pear push.19 

18 Door push.19 

19 Wall push.19 

20 Floor push.20 

21 Door pull attachment.22 

22 Wire joint first operation.25 

23 Wire joint second operation.25 

24 Wire joint insulating.25 

25 Section of house showing wiring.29 

26 Bell with ground return.30 

27 Pushes in multiple.31 














Vlll LIST OF ILLUSTRATIONS 

Fig. Page 

28 Bells in series.31 

29 Bells in multiple.31 

30 Two bells and two pushes.32 

31 Two bells and two pushes.32 

32 Two bells, two pushes and one battery .... 33 

33 Double contact push.33 

34 Grounded bell.34 

35 Tongue test of wiring.38 

36 Knife test of wiring.38 

37 Knife test of wiring. . ... 39 

38 Metallic thermostat.40 

39 Mercury thermostat.41 

40 Mercury thermostat circuit.42 

41 Water level alarm.44 

42 Lever water level alarm.45 

43 High or low water level alarm.45 

44 Window spring for burglar alarm.47 

45 Burglar alarm—closed circuit.47 

46 Special bell connection for burglar alarm ... 48 

47 Special bell connection for burglar alarm ... 49 

48 Burglar alarm and relay.60 

49 Window-shade contact spring.51 

50 House wired for burglar alarm.52 

51 Door trip alarm.53 

52 Annunciator drop . . . : . .... 55 

53 Needle drop.56 

54 Needle drop indicating.56 

55 Pendulum drop.57 

56 Annunciator drop circuit.58 

57 Simple annunciator circuit.59 

58 Annunciator and fire call circuit.60 

59 Single-wire room and fire call.61 















INTRODUCTION 


An electric bell depends for its action on the 
fact that a piece of iron wound with insulated 
wire becomes a magnet and will attract another 
piece of iron just so long as an electric current is 
allowed to travel through the wire. 

The instant the current ceases, the magnetism 
also ceases, and the attracted piece of iron (termed 
the armature) is no longer held in contact. 

The general construction of an electric bell 
is shown in Fig. 1. M M are coils of insulated 
wire wound on soft iron cores. A is a soft iron 
armature mounted on a flat spring so that it is 
normally kept a slight distance away from the 
soft iron cores. ^ is a brass screw with a plat¬ 
inum tip touching a platinum disc on a spring 
attached to the armature. 

When the push button P is pressed down, its 
two brass springs touch each other, the current 
from the battery cell B then flows through the 
wire IV, through the push P, through the 
coils M M, along A to the platinum disc, out 



X 


INTRODUCTION 




Fig. 1 



























































































INTRODUCTION 


XI 


at S, which touches this disc, and back to the 
battery. 

The instant this is done the current causes the 
iron cores to become mag-nets, they attract A, 
which then breaks contact at .S'. The spring 
mounting of A causes it to jump back to its 
first position, .S' then touches the platinum disc 
again, the current flows as before, and the arma¬ 
ture is again attracted only to break contact 
with .S' and fly back. 

This continual making and breaking of the 
circuit keeps up as long as the push is pressed, a 
ball mounted on A by means of a rod strikes 
against the gong G causing a continuous ringing 
of the bell. The wires leading between the bell, 
battery cell and push must all be insulated, that 
is, covered with cotton, rubber, etc., which pre¬ 
vents the leakage of current should two wires 
cross each other. Copper wire is mostly used for 
circuits indoors, the details of the kind and size 
of wire will be given later on. 

The main parts of an electric bell circuit are 
then—the battery to supply the electric current; 
the circuit, or wires, to carry this current; a push, 
or circuit breaker, to control the current flow; 
and a bell to utilize the current. 





CHAPTER I 


The Battery 


The Battery Cell. The battery cell most used 
in electric bell work is the Leclanche, or some 
modification of it. 

The Leclanche battery cell is shown in Fig. 2, 



where / is a glass jar, Z a rod of zinc, and P a jar 
of porous earthenware containing a carbon rod 
surrounded by powdered carbon and peroxide of 
manganese. 


















2 


ELECTRIC BELLS AND ALARMS 


In setting up this cell about four ounces of 
sal ammoniac (chloride of ammonia) are put into 
the jar and enough water added to come about 
half way up the jar. 

The porous jar P and the zinc Z are then 
inserted, and the cell is ready for use in a few 
minutes after the liquid has soaked through the 
earthenware into the carbon-manganese mixture. 
Water is often poured into the porous jar through 
holes in its top to hasten this wetting. 

Wires are clamped by nuts or set-screws to the 
negative terminal on the zinc or the positive ter¬ 
minal on the carbon, it generally not being of 
consequence which terminal is attached to either 
wire of the circuit. 

A battery cell could be constructed without the 
manganese, using simply a plate of carbon and 
a rod oj zinc, but hydrogen gas would be gen¬ 
erated on the carbon plate when the cell was work¬ 
ing and would stop the current flowing. 

This is called polarization, and peroxide of man¬ 
ganese is a de-polarizer, because it combines with 
this hydrogen gas almost as fast as it is generated, 
and prevents, to a great extent, the polarization. 

But it does not stop it entirely, as will be seen 
if the Leclanche cell is kept working above its 
capacity. Then the hydrogen is generated too 
fast for the manganese to destroy it, and the cell 


THE BATTERY 


3 


ceases to work. In this case a rest will often 
restore the cell to its former power. 

Cells which have been almost unable to make 
a bell give even a single tap have been found 
good again when allowed to remain at rest over 
night. 

In setting up a battery cell no liquid should be 
splashed on the brass terminals or corrosion will 
take place. Every metal surface where connec¬ 
tion is made to allow electric current to pass must 
be clean and bright, and all screws, or nuts, hold¬ 
ing wires must be screwed up tight so that the 
wires are firmly clamped. 

Loose or dirty connections are the cause of 
probably eight out of every ten troubles affecting 
bells and batteries. 

When the fluid in a Leclanche cell becomes 
milky, more sal ammoniac must be added. Or, 
better still, throw out the old solution, wash the 
porous jar thoroughly in clean water, scrape the 
zinc bright, and half fill the cell with fresh solu¬ 
tion. 

The zinc wearing away rapidly or becoming 
covered with crystals, and a strong smell of am¬ 
monia, show generally that the cell is being worked 
too hard, or that the current is leaking where it 
should not. 

A zinc rod in a cell working the average door 


4 


ELECTRIC BELLS AND ALARMS 


bell should last for six months, the porous jar for 
a year. 

The Dry Cell. The Leclanche cell being a 
cell with much free liquid is liable to dry up if 
not watched. The dry cell (Fig. 3) is a modern 



Fig. 3 


form of the Leclanche where the liquid is held by 
an absorbent material, such as blotting paper, or 
plaster. 

A typical dry cell* is shown in the figure. An 

*For full description of this class of battery see No. 3 
Book on “Dry Batteries.” 





































































THE BATTERY 


5 


outside case of zinc is lined with blotting paper 
dampened with chloride of zinc and sal ammoniac. 
A carbon rod is then inserted in-the centre and 
packed around with carbon dust and peroxide of 
manganese. The latter mixture is also somewhat 
dampened. 

Molten wax, or a suitable composition, is then 
poured on top of the contents of the cell to seal it 
up and prevent the evaporation of the fluid. A 


rf— 


T 

i 

i 

i 

i 


Z 

C 


£322 


Fig. 4 




terminal on the carbon rod and another on the 
zinc case complete the cell. 

The voltage of both the Leclanche and the dry 
cell is about 1.45, when it goes below this it in¬ 
dicates that the cell is worked out. 

The two cells described are known as open- 
circuit cells and are only intended for intermittent 
working. 

When a current is needed for a long period at 
a time a closed circuit cell should be used, such as 
the gravity Daniell cell. 




















6 


ELECTRIC BELLS AND ALARMS 


The Gravity Daniell Cell. The gravity cell, 
Fig. 4, has a zinc block Z suspended from the 
side of the jar 'and a number of copper leaves C 
standing on edge at the bottom. A quantity of 
hluestone (sulphate of copper) is poured over the 
copper leaves and the jar filled with water. 

During the working of this cell, copper is de¬ 
posited on the copper plate, and sulphate of zinc 
formed at the zinc. To hasten the action a small 
quantity of zinc sulphate can be added to the 
solution when setting up the cell. 

The name of this cell comes from the fact that 
the copper solution being heavier remains at the 
bottom of the jar. If the cell is not worked 
enough, all the solution will become blue and the 
zinc will blacken. If very dirty from this cause, 
remove the zinc, scrape and wash it thoroughly. 
Throw out all the solution, add new sulphate and 
water and replacing the zinc, then put the cell 
on short circuit by connecting the copper and 
zinc together for a few hours. 


E. M. F. The e. m. f. of a gravity cell is within 
a fraction of one volt, its current nearly one-half 
ampere. 

Warmth makes it give a greater current; on 
no account let a gravity cell freeze. 


THE BATTERY 


7 


Resistance of a Cell. The fluids in a cell do 
not conduct electricity as well as copper does; they 
offer more resistance and thus reduce the current 
output. 

The internal resistance of a cell may be low¬ 
ered by using large zinc plates curled around the 
porous pot. . 

The Samson cell has a large zinc plate bent in 
the form of a cylinder, the carbon-manganese 
combination standing in the centre of it. 

The dry cell also has a large zinc, the internal 
resistance being thus much lowered, the current 
output is increased. This is by reason of Ohm’s 
law, which teaches that to increase the current 
flow, either the voltage of the battery must be in¬ 
creased, or the resistance decreased. 

But increased current means lessened life; there 
is only just so much energy in a cell mainly de¬ 
pendent on the quantity of chemicals. 


Grouping of Cells. Cells may be grouped in a 
battery to get increased voltage, or increased am¬ 
perage. When connected for the* former, they 
are in series, the carbon of one is connected to the 
zinc of the next, and so on. 

If all the carbons are connected together and all 
the zincs, they are in multiple, and will give the 


8 


ELECTRIC BELLS AND ALARMS 




same voltage as of one cell but the combined am¬ 
perage of all. 

In ordinary bell work the series is the general 
connection, the higher the resistance of the cir¬ 
cuit, or the longer the wires, the more voltage is 
required. 



# 



. / 


s 


CHAPTER II 

Bells and Pushes 

Electric Bells. The two main types of house 
bells are the iron box and the skeleton. 

The iron box has a cast-iron frame, or base, and 
a cast- or stampecl-iron cover over the mechanism. 

The skeleton bell has an iron frame but no 
cover, and is generally better finished and more 
expensive than the iron box bells. 

For fire alarm purposes, mechanical bells or 
gongs are made, in which a clockwork mechan¬ 
ism causes the hammer to strike the gong upon 
being released by electromagnetism. 

Marine or waterproof bells have an iron cover 
fitting tight over a rubber gasket; they are for 
marine, or mining, work. 

Polarized, or magneto, bells are used in tele¬ 
phone work, and are rarely operated by a battery, 
but have a miniature dynamo generator operated 
by hand, or power, to supply the actuating cur¬ 
rent. 

Most bells are classed for size by the diameter 
of the gong, a four-inch bell being one with a 
gong four inches in diameter; a six-inch bell one 
with a six-inch gong, and so on. 


10 


ELECTRIC BELLS AND ALARMS 


According' to the use for which they are in¬ 
tended, bells may be vibrating, as before described, 
single-stroke, shunt or short-circuiting, differen¬ 
tial, continuous-ringing, or adapted for circuits of 
high voltage. 

The Single-stroke Bell. The bell before de¬ 
scribed, and again shown in Fig. 5, is a vibrating, 
or trembling, bell. It is often desired to have the 
hammer give only one stroke for each pressure of 
the push, as in signaling with a code of taps; in 
this case a single-stroke bell is used. The circuit 



* 


Fig. 5 Fig. 6 Fig. 7 

from the binding posts is then directly through 
the magnet coils without any break at the contact 
screw, as in Fig. 6. 

In adjusting such a bell to give a clear sound, 
press the armature up against the iron magnet 
cores and then bend back the hammer until it just 
clears the gong. The spring of the hammer wire 
will carry the hammer sufficiently forward to hit 
the gong. The tone will be clearer than if the 
hammer dampered the gong by pressing against 
it when the armature was nearest the core. 




























































BELLS AND PUSHES 


11 


By bringing out a third connection, a vibrating 
bell may be made both single stroke and vibrating. 

The Shunt Bell. There is a form of bell, 
Fig. 7, known as the shunt, or short circuit bell, 
which is often used when two or more are to be 
connected in series, as will be seen in the descrip¬ 
tion of circuits. In this bell the circuit through 
the magnets is not broken at the contact screw, 
but the forward movement of the armature short 
circuits the coils. 

As the short, or shunt, circuit is very much 
lower in resistance than the wire on the magnet 
coils, the main current flows around the latter and 
they do not become energized. The sparking at 
the shunting contact screw is much less than it 
would be at the ordinary breaking contact screw, 
and the platinum points last longer. 

The Differential Bell. Sparking at the break¬ 
ing contacts of an electric bell is detrimental to 
the platinum points, and many remedies have been 
devised to overcome it. 

Sparking is due to the self-induction of one 
turn of the wire coil acting on its neighbor, and 
this property is utilized in the gas engine, or gas¬ 
lighting spark coil, where a fat spark is needed to 
ignite gas. 


12 


ELECTRIC BELLS AND ALARMS 


The differential bell has two windings in oppo¬ 
site directions. The action of one would be to 
produce an N-pole at one end and an S-pole at 
the other. But the second coil produces poles just 
the opposite, as the polarity of a magnet depends 
on the direction in which the current flows around 
it. 

Where the current flows around the first wind¬ 
ing the armature is attracted and its spring con¬ 
tact meets the contact screw and allows the cur¬ 
rent to divide, part flowing through the first coil, 
the other flowing in the reverse direction in the 
opposite way. One coil would tend to produce 
an N-pole where the other coil produced an S-pole, 
and these opposite poles would so neutralize each 
other that there would be no magnetism. 

The armature would therefore be pulled back 
by its spring when both coils were thrown into 
circuit. In so doing it would cut out one coil 
and the same series of operations would recom¬ 
mence. 

As a spark is normally produced where mag¬ 
netism is lost by a break of circuit,* no spark ap¬ 
pears, as magnetism is produced by a break of 
circuit in this case. 


*For a full explanation of self-induction see No. i of 
this series. 



BELLS AND PUSHES 


13 


Continuous-ring - Bell. In some classes of bell 
work, such as burglar alarms, it is desired that the 
bell when once started shall continue to ring until 
stopped by the person called. In this case a con¬ 
tinuous-ringing bell is needed, such as in Fig. 8. 

When the push P is pressed, the current flows 




Fig. 8 


in the usual way through contact screw L, arma¬ 
ture spring A, magnet coils M M, battery B, back 
to P, and the bell rings. But on the first forward 
movement of the armature it releases the spring 
contact S, which flies forward and makes contact 
at U. The circuit is now from B, through M M, 







































14 


ELECTRIC BELLS AND ALARMS 


to A, thence through L and S, to U and back 
to B. 

The bell will continue to ring until the spring 
contact 5 is moved back and caught by the pro¬ 
jection on the armature A. 

A continuous-ring attachment is also made and 
sold in most electrical supply stores, which is com¬ 
plete in itself and can be applied to any bell. 



Waterproof Bells. In Fig. 9 is an example of 
a waterproof bell where the mechanism is almost 
all entirely encased in a waterproof brass case. 

The ciicuit is made and broken inside the case, 
but the magnet cores project through it and act 
on a second armature placed outside. This sec¬ 
ond armature carries the hammer which strikes 
the gong and is governed in speed by the contact¬ 
breaking armature inside. 




























































BELLS AND PUSHES 


15 


Forms of Bell Gongs. In order to provide a 
variety of sounds, bells are provided with gongs 
of various shapes. 

Fig. 10 shows the ordinary form of gong. 



Fig. 10 Fig. 11 Fig. 12 Fig. 13 


Fig. 11, a tea gong; Fig. 12, a cow gong; and 
Fig. 13, a sleigh bell. 

A coil of steel wire is also used, as in Fig. 14, 
which on being struck by the hammer gives a 
pleasant but not loud tone. 



Fig. 14 


The Buzzer. The buzzer is the mechanism of 
a vibrating bell less the hammer and gong. As 
the armature vibrates it makes a buzzing noise 
which does not carry as far as the sound from 
a struck gong. It is used chiefly for a desk call 













16 ELECTRIC BELLS AND ALARMS 

and in telephone exchange work, or any place 
where general attention is not desired to the signal. 

Operating Bells at a Distance. When it is 
desired to ring a bell situated at a considerable 
distance from the push, the resistance of the line 
becomes objectionable. 



On lines of 500 feet, No. 18 copper wire and 
upwards, the battery necessary would be very 

large, two small batteries and a relay would prove 
more satisfactory. 

In Fig. 15 the circuit of a simple form of relay 
is given. An adjustable contact screw C is placed 
where an extension N of the armature A can strike 

























































BELLS AND PUSHES 


17 


it. This extension is provided with a platinum 
contact. The connections are as in the figure. 

When the push P is depressed, the current from 
the main battery M energizes the electromagnet E, 
and the armature A being attracted, contacts S' 
and C meet. These contacts close the second cir¬ 
cuit containing the bell 3 and the local battery L. 

The relay resembles a second push near the 
bell, but controlled by current from a distance 
instead of being depressed by hand. Its advan¬ 
tage consists in it needing but a very weak cur¬ 
rent to move the armature A, which is held back 
by a light spring, or by gravity. 

The relay may then be set near the bell and 
the wires from the push may be of a very great 
length. Battery L, which actually rings the bell, 
will thus only have to work through a few feet 
of wire. 

Reducing Resistance of a Bell. Sometimes 
it is desired to reduce the resistance the bell coils 
offer to the current, the bell then working over a 
very short line with few cells of battery. Or 
the bell coils may have been wound with fine 
wire for large battery voltage and a long line. 

The bell coils may be put in multiple, the cur¬ 
rent then dividing and one-half going through 
each spool. 


18 


ELECTRIC BELLS AND ALARMS 


Untwist the joint between the spools near the 
yoke or iron bar to which the spools are attached. 
Join one of these ends to the wire at the armature 
end of the other spool and the second untwisted 
end to the armature end wire of its neighboring 
spool. Use short pieces of insulated wire for 
these extra connections. 

The current now instead of having to go 
through one spool and then the other, can branch 
through both at once. 

The resistance to the current of one spool is 
half the resistance of two, the current through one 
spool will therefore be twice that through the 
two spools as at first connected. And as there are 
two paths for it, each one-half the first resistance, 
the total will be only one-fourth the resistance 
of the ordinary series arrangement. 

The same size battery will therefore send four 
times the current through the spools in multiple 
than when they are in series. 

It is to be noted that the wire on one spool is 
wound in the reverse direction to that on the 
other. The reason will be apparent if the two 
spools and yoke are considered as merely one 
spool bent in a U or horseshoe form. 

If both spools were wound in the same direc¬ 
tion they would be in opposite directions when the 
U were straightened out, and would cause like 


BELLS AND PUSHES 


19 


poles at the same ends. These poles would neu¬ 
tralize one another, so that there would be no 
magnetic attraction. 

This can be readily proved by joining together 
the two yoke ends and the two armature ends of 
the spool wires. Then pass the current through 
these two joined connections. 



The Push Button. Push buttons, or pushes, 
are made in a variety of forms, with metal, wood, 
hard rubber, or porcelain bases. 

Fig. 16 has a metal base, and is suitable for 
a front door. 

Fig. 17 is a wooden pear push, and is attached at 
the end of a cord which has the two conductors 
braided in it, each, however, having its own in¬ 
sulation. 

Fig. 18 is a plate push for an outside door. 














20 


ELECTRIC BELLS AND ALARMS 


Fig. 19 is either of metal, wood, or porcelain, 
and is the shape most commonly used. 

A three-point push has three contact springs. 
One is movable by means of the button, one is 
below the movable spring, and the third is above 
it. 


When the push button is not being depressed, 



the movable spring makes contact with the upper 
spring. But when the button is depressed, these 
two springs part, and the movable spring makes 
contact with the lower one. 

This style of push is used for special bell and 
annunciator work, as will be described later. 

The form of combination floor and table push in 
Fig. 20 is the most solidly constructed device of 
its kind. The lower part is set in a hole bored 
in the flooring, the metal flange keeping it in 
place and preventing its slipping through. 









































































BFLLS AND PUSHES 


21 


The floor push attachment works as follows: 
The central metal rod is divided into two parts 
B D, by an insulating piece of hard rubber. When 
depressed against the action of the spiral spring 
by the foot, the upper part B connects together the 
contact springs A C, closing the circuit of bell 
and battery. These contact springs are insulated 
from each other by a hard rubber block R. 

From the table push a cord containing two in¬ 
sulated wires leads to the two parts of the rod 
at B and D. When the push centre is pressed 
down, the push springs come together and practi¬ 
cally short circuit B and D, which completes the 
circuit of bell and battery. At any time the centre 
rod may be removed, leaving a surface almost 
flush with the carpet, or floor, over which furni¬ 
ture may be moved without injury to the mechan¬ 
ism of the push. 

For a floor push alone a shorter form of the 
centre rod is also sometimes furnished which is 
not divided by insulation. The spiral spring 
keeps it clear of the lower contact A but enables 
it to always make connection with the upper con¬ 
tact B. Pressing this rod down will also short 
circuit the bell and battery so that the signal is 
given. 

A door pull attachment, like Fig. 21 , is made 
so that the ordinary form of lever pull bell may 


22 


ELECTRIC BELLS AND ALARMS 


be changed into an electric bell. Being screwed 
up near the door pull, a wire is run from the lat¬ 
ter and fastened to lever L. When the pull is 
drawn out the lever L turns on a pivot and a 
projection presses the insulated spring S against 
the metal base B. The circuit of the bell and 
battery being thus closed, the bell rings. 



Indicating Push Button. A push button is 
made which contains in the base a small electro¬ 
magnet in series with the line. An armature on 
a spring is fixed near the magnet poles. When 
the push is depressed, the current travels through 
this electromagnet, and as the circuit is made 
and broken at the distant bell, it is also interrupted 
in the electromagnet. The armature vibrates in 
unison with the bell and thus gives an audible 
indication that the bell is ringing. 


















CHAPTER III 


Wiring, Circuits and Troubles 

The Wire. The size of the copper wire used 
in bell work is No. 16, or No. 18, B and S gauge, 
and sometimes smaller, such as No. 20 to 22. 
But smaller wire than No. 18 has too much re¬ 
sistance, and would necessitate a larger battery 
power, even if its mechanical strength were not 
too low. The Insulating coverings are cotton satu¬ 
rated with paraffin wax or compounds. 

The covered wires are variously known as an¬ 
nunciator, office, or weatherproof wire, these terms 
being mostly for distinction of the coverings and 
not for the use to which the wire would be put. 

Annunciator wire has two layers of cotton 
merely wrapped around the copper and then satu¬ 
rated with paraffin. v 

Office wire has the two cotton layers braided, 
the inside one being filled with a moisture-repel¬ 
ling compound. 

Both office and annunciator wires have their 
outside coverings filled with paraffin and highly 
polished. 

From the ease with which annunciator wire is 


24 


ELECTRIC BELLS AND ALARMS 


stripped of its cotton covering, the braided office 
wire is to be preferred. These coverings are made 
in a variety of colors. 

Weatherproof covered wire is mostly used for 
electric light work, but the sizes given above are 
good for bell work, although their larger outside 
diameter makes them harder to conceal. 

The approximate number of feet to the pound 
of office and annunciator wire is given in the 
table. 


Office 

Wire. 

Annunciator Wire. 

No. 

Feet per lb. 

No. 

Feet per lb. 

12 

35 

18 

180 

14 

55 

20 

225 

16 

95 



18 

135 




Joints. Upon the care with which a joint is 
made much depends, a loose or poorly made joint 
will offer much resistance to the current. 

The correct way to start a joint in annunciator, 
or office, wire is shown in Fig. 22. About three 
inches of each wire to be joined is bared of its 
insulation and scraped bright. The ends are then 















WIRING, CIRCUITS AND TROUBLES 


25 


bent at right angles to each other, hooked together 
and one end firmly twisted around the other, as 
shown in Fig. 23. Any projecting pieces are cut 
off, and the joints should then be soldered to pre¬ 
vent corrosion. 



Fig. 22 




Jo 


=czz2zzzzzza 


Fig. 23 



}7TZ.7 JT £uU 


Fig. 24 


Adhesive tape (“friction tape”) is wrapped 
around the joint, Fig. 24, and pressed firmly to¬ 
gether so that there is no chance of its unravelling. 
The tape wrapping should extend across the joint 
and on to about a half inch of the insulation 
around each wire. 



















26 


ELECTRIC BELLS AND ALARMS 


Running the Wires. To detail all the opera¬ 
tions of installing a complex system of bell, alarm 
and annunciator wires would be impossible from 
the reasons that conditions vary and space is lim¬ 
ited. General directions will then only be given 
to enable the inexperienced to run such wires as 
may be needed in ordinary domestic work and to 
guard against the most common causes of failure. 

Wires may be run in tin tubes to prevent the 
depredations of rats and mice, or they may be run 
with simply their own covering for protection; it 
is presumed the latter is undertaken. 

In a case where the building is of frame and 
in course of erection the task is much simplified. 

Having first decided upon the plan, number of 
bells, pushes, etc. and their location, proceed to 
run the wires first in order that the'pushes, bells, 
etc. may not be injured. 

But where the house is already occupied, as in 
the majority of cases likely to be met with by the 
reader, the bell and battery may be set first. 

Take the case of an ordinary door bell with the 
push at the front door, the bell in the kitchen and 
the battery in the cellar. If possible get the wire 
on two spools; it will simplify matters if both 
wires are of different colors. Starting at the push, 
have a foot of each wire for connection and slack, 
and fasten each wire lightly to the woodwork with 


WIRING, CIRCUITS AND TROUBLES 27 

staples, or double-pointed tacks, never putting two 
wires under one staple nor driving in a staple so 
it cuts the insulation. Some cases will require a 
staple about every foot, on straight runs some¬ 
times every three feet. 

In many cases the wires can be partly con¬ 
cealed in the angle between a moulding and the 
wall, or even in a groove of the moulding itself. 
When running along a skirting, the wires may 
often be pushed out of sight between it and the 
floor. Do not attempt to draw the wires too 
tight or the changes of the weather may break the 
wires when the woodwork shrinks or swells. 

The wires will be, one from the push to the 
bell, one from the push to the battery, and one 
from the bell to the battery. So it is probable 
that the second wire can be run right through a 
small hole bored in the flooring under the push, 
but inside the front door. In this case it will 
be perhaps easier if the spool be left in the cellar 
and the end of the wire be pushed up from below 
and stapled to the woodwork near the push, leav¬ 
ing the cellar work to the last. Only one wire 
will be run then direct to the bell upstairs and 
it can be better concealed than two. 

If necessary it may be drawn under a carpet 
and not stapled, or it can often be forced into the 
crack between two boards. But if not, run it 


28 


ELECTRIC BELLS AND ALARMS 


along the skirting, following the walls until it 
reaches below the bell. It is often better to go 
entirely around a room than to cross below a 
door. 

If a door must be crossed the wire may either 
run up one side of the frame and down the other 
or laid beneath the carpet on the sill. The former 
is preferable, but takes more wire. 

In many houses the bell wire as well as the bat¬ 
tery wire may be run across the cellar beams 
(Fig. 25), in which case bore a second hole for it 
near the push; do not draw it through the same 
hole as the push to battery wire. And, of course, 
here work upwards with the spool in the cellar. 

Having reached the bell location, run the third 
wire down into the cellar to the battery. Now 
connect up the push, baring an inch or so of each 
wire, push them through the holes provided in 
the push base, screw down the push base and 
clamp the wires under the washers through which 
the connection screws run. Do this neatly, be sure 
the ends of the wires do not stick out, cut off 
what is left free of the bared ends. Then con¬ 
nect the battery to the wire from the push and the 
wire from the bell. The last thing is to scrape 
and fasten the bell wires to the bell binding posts. 
Do this so that they cannot come loose and that 
they make good contact. 



Fig. 25 







































































































30 


ELECTRIC BELLS AND ALARMS 


The bell should now ring properly when the 
push is pressed. 

To sum up, one wire leads from one spring 
of the push to the bell, one wire from the other 
spring of the push to the battery, and another wire 
from the remaining binding post on the bell to the 
remaining binding post on the battery. It is im¬ 
material whether the zinc terminal or the carbon 
terminal go to the bell or push. 

Combinations of Bells and Pushes. One of 

the wires in a bell circuit may be replaced by 
the ground (Fig. 26). Connection may be made 
to a gas or water pipe or to a metal plate buried 
deep in damp earth. Any wire fastened to such a 



plate must be thoroughly soldered to it or a voltaic 
action will be set up, which will eat it away at the 
point of contact. 

When one bell is to be rung from two or 
more points the pushes are to be connected in 



































WIRING, CIRCUITS AND TROUBLES 31 

multiple (Fig. 27) as if they were in series; all 
would have to be closed to complete the circuit. 

If two bells are to be operated from one push 



they may be in series (Fig. 28), but in this case 
one of them must be arranged for single stroke. 



If both were vibrating bells the armature of one 
would not vibrate in unison with the other arma¬ 



ture and the result would be irregular contact 
breaking and intermittent ringing. 

A preferable connection for two or more bells 










































































32 ELECTRIC BELLS AND ALARMS 

and one push is Fig. 29, where the bells are in 
multiple. This requires more current than the 
series method. 



To ring two bells from either one of two points, 
the arrangement in Fig 30 will answer. It re¬ 
quires only two wires or one wire and ground 
return, but two batteries. As both bells are in 



multiple both will ring, the one nearest the push 
being depressed ringing the loudest. This is a dis¬ 
advantage. If the series arrangement in Fig. 31 




























































WIRING, CIRCUITS AND TROUBLES 


33 


be selected, one bell must be arranged for single 
stroke. Both bells will ring with equal power. 

In Fig. 32 only the distant bell rings, the cir¬ 



cuit having only one battery but three wires, or 
two wires and ground return. 

A plan where two batteries are needed but only 
two wires, or one wire and ground is in Fig. 33. 



Fig. 33 


here, making one contact when depressed and a 
second one when not being touched. 

In this figure only the distant bell rings. 









































































34 


ELECTRIC BELLS AND ALARMS 


Faults in Bells. On examining many electric 
bells it will be noted that only one binding post 
is insulated from the frame when the latter is 



of iron (Fig. 34). As the armature spring S is in 
electrical connection with the frame F by reason 
of its metal screws and support, the circuit may 
run from the insulated post U to the magnet coils, 
thence through the insulated contact screw C 
through tlie armature spring (when it is making 
contact) and through the frame to the uninsulated 
post /. 

This saves labor, wire and complication, but if 
the insulation of the post U, the wires W V, or the 
contact screw C be injured, the current may take 
a short path back to the frame. 

If C were thus grounded, the bell would act as 
a single-stroke bell. 

If U were grounded, the bell would not ring 
































WIRING, CIRCUITS AND TROUBLES 


35 


at all, as that would be a short circuit on the bat¬ 
tery between / and U and the latter would also 
result if the bare wire were touching the frame 
at V. 

If the bare wire touched the frame bevond M M, 
that is, along W, it would be a single-stroke bell, 
as if C were grounded. 

As any one of these faults is likely to occur, 
they should be looked for when the bell acts im¬ 
perfectly, or not at all. 

A very common fault in a bell is when its arma¬ 
ture sticks to the cores and thus does not make 
contact with the contact screw. This may be from 
a weak spring or because of the loss of the pieces 
of brass inserted in the ends of the cores to keep 
the armature away from actual contact. A piece 
of a postage stamp stuck over the core end will 
often help out in the latter case. 

A high screeching noise from the armature vi¬ 
brating too rapidly but with too little play, may 
be from excessive battery power or the contact 
screw being too far forward. The former will 
generally be detected by the violent sparking as 
well as the rapid vibration. 

In very cheap bells the platinum contacts may 
be replaced by German silver or some other metal. 

Platinum is necessary because the sparking 
would soon corrode other metals, but it is very 


36 


ELECTRIC BELLS AND ALARMS 


expensive. To test for platinum put a tiny drop 
of nitric acid on the suspected metal. If bubbles 
or smoke appear it is not platinum. After apply¬ 
ing this test in any case however, carefully wash 
off and remove all traces of the acid, as it will cor¬ 
rode the metal into which the platinum is riveted. 

Dirty contacts will decrease the current in the 
bell coils and it will not work well, if at all. 

Loose contact screws and wires also give 
trouble. The adjusting of the contact screw is of 
the utmost importance, and should never be at¬ 
tempted unless it is clearly necessary. 

Faults in Line. In looking for a fault in a 

bell circuit make sure the battery is working; if 
only one or two cells, put the ends of two wires 
attached to the terminals on the tongue: a metallic 
taste will indicate current. 

Then see that the circuit wires are firmly 
clamped in the terminals and no dirt or corrosion 
on the connections. 

Next examine the push button and see that the 
wire connections at the springs are perfect. 

If there is no movement of the bell at all when 
the push is pressed in, take a pocket knife or 
screw driver, and touch the blade across the push 
springs. If there is current flowing sparks will 
be seen when the blade breaks contact between 


WIRING, CIRCUITS AND TROUBLES 37 

the springs. If there are no sparks, detach the 
wires from the bell and twist the bare ends to¬ 
gether. Then try again for sparks—they may 
now be very minute. The tongue test is good here. 

If current is detected, examine the bell for the 
defects first mentioned. 

But if no current is found at the push now the 
wires are broken somewhere. 

First short circuit the push springs by insert¬ 
ing a knife blade or piece of wire so as to touch 
both of them. Then touch the two wires at the 
bell, one to each side wire coming from the mag¬ 
net coils. If current is up to the bell and the coils 
are all right, a single stroke should result. 

Replace the wires in the binding posts, clean 
the platinum on both contact screw and armature 
spring and try the adjustment. Troubles in the 
bell will be mostly similar to those before men¬ 
tioned. 

If no current has been obtained at either bell 
or push, and the battery is in good working order, 
the line must be tested for a cross or break. 

If the wires are touching each other (Fig. 35) 
at some bare spot 5* between the bell and the bat¬ 
tery, it will be shown by the metallic taste upon 
detaching one wire from the battery and laying 
it on the tongue T, together with another wire W 
from the disconnected terminal of the battery. The 


38 


ELECTRIC BELLS AND ALARMS 


current will travel from the battery to the cross 
at S, then back along the second circuit wire to 
the tongue and through the short wire to the 
battery. 



If no current is obtained in this way it is prob¬ 
able that the wire is broken. 



The easiest way to find this is to take a bell ^ 
to the battery and connect it between the circuit 
wires and the battery (Fig. 36). 

Then with a sharp knife carefully cut away a 



















































WIRING, CIRCUITS AND TROUBLES 39 

\ 

little piece of the insulation from each wire beyond 
the bell and battery and short circuit the bared 
spots with the knife blade K. Keep working 
towards the push. The bell will ring each time 



at K K until the break D is passed, at C it will 
not. It becomes an easy matter then to locate 
it. 

If the bell and push are far apart, as in Fig. 37, 
a break between the push and the bell may be 
found as shown. With the knife blade K at differ¬ 
ent points the bell will ring, but after passing the 
break D it will not ring. 

Such simple tests as are here given can be car¬ 
ried out by any one, but far better results will be 
obtained if the reason for each is first learned. 

This can be readily done by a careful study of 
the diagrams and text. 
















CHAPTER IV 
Alarms 


Fire Alarms. Thermostats, heat alarms and 
fire alarms are all practically the same, the term 
thermostat being applied principally to the appa¬ 
ratus which closes the electrical circuit. 



c 


Fig. 38 


Thermostats act on the principle that heat causes 
expansion whether of substances, liquids, or gases. 

The degree in which different substances ex¬ 
pand varies for the same increase in temperature. 
This fact is used in a common form of thermo¬ 
stat shown in Fig. 38. A strip of wood or hard 
rubber R has a strip of thin sheet metal A riveted 
to it. This compound strip is held at one end by 
























ALARMS 


41 


a lug L screwed fast to a baseboard. Upon an 
increase of temperature the hard rubber expands 
more than the metal strip and the compound strip 
bends towards the adjustable contact screw A. 
Upon touching the latter, the circuit through the 
bell B, battery C and the metal strip 5* is com¬ 
pleted, and the bell rings. A contact screw can 
be arranged at the other side of wS' R, which will 



give warning of a decrease in temperature, as the 
rubber contracts more than the metal strip. 

In some thermostats of this character two metals 
having different coefficients of expansion, such as 
steel and brass, are used instead of metal and hard 
rubber. 

Thermostats of this nature are much used in 
incubators, and they can readily be combined with 
electric apparatus to open or close hot-air valves, 





























42 


ELECTRIC BELLS AND ALARMS 


clampers, etc., and thus regulate the supply of 
hot air, hot water, or gas. 

A thermostat much used in fire alarm work has 
a thin metal chamber which is air tight. An in¬ 
crease of temperature causes the air to expand, 
which swells out the walls of the chamber and 
closes an electric circuit. 


A 




B 

© 


Q- 


■© 


0 

i 

1 

i. 

0 




Fig. 40 


The mercurial thermostat shown in Fig. 39 has 
a glass tube T and bulb containing mercury. Into 
each end is sealed a platinum wire P P. Upon 
the temperature rising to a predetermined degree, 
the expanded mercury completes the circuit be¬ 
tween P P and the battery C and bell B are put 
in operation. 

Fig. 40 is the open circuit system most used by 


















































ALARMS 


43 


the fire alarm companies, only one circuit of six 
thermostats being illustrated. 

It will be seen that if any thermostat closes the 
circuit between the outer and inner wires of the 
ring A B, current will flow through the corre¬ 
sponding drop of the annunciator and will attract 
the armature A of the relay. This will cause the 
bell to ring. As the relay is connected to the an¬ 
nunciator as before shown for the annunciator bell, 
it offers a common path for any drop to the bat¬ 
tery. Thus the bell will ring for any circuit, but 
the individual drop only will fall. In a simpler 
circuit the relay may be dispensed with and a 
vibrating bell only used. 

Thermostats may be operated on open or closed 
circuits, that is, they may give the alarm by clos¬ 
ing a circuit and ringing a bell, or by opening one 
and releasing a contact spring as in the burglar 
alarm system to be described later. 

Water Level Alarms* Where it is desired to 
signal the rising or falling of water in a tank 
above or below a given point, a water level in¬ 
dicator as in Fig. 41 may be used. 

A hollow ball H is mounted on the end of a 
rod which slides vertically in guides, not shown. 
Adjustable stops ^ ^ press against a spring 
arm R , pressing it up or down, according as the 


44 


ELECTRIC BELLS AND ALARMS 


water level is rising or falling. If rising, R makes 
contact with the adjustable screw A, if falling, 
with D, in both cases completing the electrical cir¬ 
cuit of the battery C and bell B. 



Fig. 41 


Another and simpler form is shown in Fig. 42, 
where the ball H is mounted on the end of a 
lever L pivoted at P, its rise or fall completing 
the circuit of B and C as before. 





























ALARMS 


45 


Where it is desired to give a different signal for 
the rise and the fall of level, two bells B and E 




(Fig. 43) may be used connected as shown. The 
rising of the ball will ring bell B, and its fall, 
bell E. 























































46 


ELECTRIC BELLS AND ALARMS 


In both forms of indicator, a means must be 
provided that an undue rise may not bend the 
lever. This may be accomplished by using contact 
springs instead of contact screws; it is, however, 
then harder to adjust the indicator to fine differ¬ 
ences of level. 

In all cases the contacts must be faced with 
platinum to prevent corrosion. 

Burglar Alarms. A burglar alarm is a device 
for indicating the opening of a door or window, 
by the ringing of a bell or operation of an annunci¬ 
ator The contact apparatus at the points.to be 
protected may either open an electrical circuit or 
close one, in the latter case being mere modifica¬ 
tions of push buttons. The simplest form is the 
latter or open-circuit method. 

The spring contact to be inserted in the door 
jamb or window frame is so constructed that 
while under pressure the contacts are kept apart 
and the circuit is open. But when the door or 
window is opened, the pressure is released and 
a spring forces the contacts together. 

Fig. 44 is an open-circuit window spring fitted 
in the window frame so that when the window 
is closed the spring lug A is pressed inwards, 
breaking contact with the base B. 

If the window is raised, the lug flies to the 


ALARMS 


4Y 


position shown by the dotted lines, and making 
contact with B, completes the circuit through bell 
and battery. These springs are fitted in the side 



Fig. 44 


of the window frame in a vertical position and 
are entirely concealed when the window is shut.* 
In the closed-circuit system the reverse hap¬ 
pens. The pressure of the closed door or win¬ 


's 



dow keeps the contacts together and its opening 
enables them to spring apart. 

In Fig. 45 is a diagram of a closed-circuit 
burglar alarm, C a cell of gravity battery, R a 





















































































48 


ELECTRIC BELLS AND ALARMS 


relay, F the fixed contact and M the movable con¬ 
tact of the spring, 5* a stud projecting through 
the base of the spring and pushed in by the closed 
door. 

When the door is closed, 5 1 being pushed in, 



the circuit of C, R, F and M is closed. The 
magnets of the relay hold the armature arm A 
forward against a hard rubber contact. But when 
S is released, the relay circuit is opened, R loses 
its power and A flies back, making contact, and 
throwing in circuit bell B and battery L. 


\ 




























































































ALARMS 


49 


A form of bell and relay combined is shown in 
Fig. 46. Here the armature A is held against the 
magnets while the circuit through the spring F 
and battery G is closed. But on opening this cir¬ 
cuit the armature flies back and makes contact 
with an adjustable contact screw ^ putting in 
circuit a local battery C. The bell is now practi¬ 



cally a vibrating bell; on a closed circuit it rings 
until the circuit is again closed or the battery runs 
down. 

A different connection of the same scheme is 
Fig. 47, where only one battery is used. This 
must be a gravity battery or some other closed- 
circuit battery. The circuit can be easily traced 
in the figure and needs no special description. 































































50 


ELECTRIC BELLS AND ALARMS 


Both of the latter schemes are inferior to one 
using a separate relay. If the circuit at the spring 
were quickly closed again the bell would either 
stop ringing, or be so hampered as to ring very 
weakly. 


Fig. 48 



A relay made as in Fig. 48 has no spring sup¬ 
port to the armature A, which falls down by grav¬ 
ity. The adjustable contact C is screwed far back, 
so that the armature must fall a considerable dis¬ 
tance away from the electromagnets before it 
makes contact. This ensures that the armature 
will not be attracted and the bell stopped from 
ringing by a re-closing of the circuit at the door 
or window spring. 

A shade spring (Fig. 49), is made for either 




















































































ALARMS 


51 


open or closed circuits. In operation, the shade is 
pulled down and its string or ring hooked on 
to H. This draws H up a trifle against a spiral 
spring and its lower end makes contact with an 
insulated spring 5* closing the circuit. If the 
shade is disturbed, the spiral spring on the lower 
part of H is released and it causes a break of 
contact with Shin the direction of the arrow. 

When made for open circuit, vS' is bent so that 


> 



Fig. 49 


while under tension no contact is made, but re¬ 
lease of tension causes the contact. 

Fig. 50 gives the wiring of two windows and 
a door on the closed-circuit system. It will be 
seen that the contact springs are all in series, 
opening a window or the door will thus break 
the circuit. 

When setting the alarm at night by connecting 
up the batteries, relay and bell, should any one 
of these springs be open the relay armature will 
not hold, and the bell rings. 














Fig. 50 

































































































































ALARMS 


53 


In this figure the relay is replaced by an electro¬ 
magnet holding up a drop shutter by magnetic 
attraction. Upon the circuit opening, this shutter 
falls, exposing a number painted on it. At the 
same time it hits a spring contact placed below 
it and closes the bell and local battery circuit. 

Door Trip Alarm. A swinging contact door 
trip can be attached over a door to ring a bell 
when the door is opened. 



Fig. 51 


In Fig. 51 the door trip is screwed over the 
door so that the lowest arm A is struck by the 
door. When the door is opened, in the direction 
of the arrow, the arm A is thrust forwards, and in 
its turn moves the contact arm C, completing the 
bell and battery circuit. But when the door is 
being closed, A swinging in the reverse direction 
does not move C and no alarm is given. 











































54 ELECTRIC BELLS AND ALARMS 

Miscellaneous Alarms. The Applegate elec¬ 
trical matting is composed of wooden slats with 
springs so arranged that the weight of any person 
stepping on it will close a circuit and ring a bell. 

It is intended to be put under the ordinary door 
mat or under stair and room carpeting. 

The Yale lock switch is a Yale lock and switch 
combined. Upon any key but the right one being 
inserted, a circuit is closed and an alarm bell is 
rung. 


i 


\ 


CHAPTER V 
Annunciators 

The Annunciator. The mechanism of an an¬ 
nunciator consists of electromagnets which allow 
shutters to drop or needles to move on the cir¬ 
cuits being closed. A bell is also rung in most 
cases to call attention to the annunciator. The 
number of the circuit is marked on the shutter, 


r 



or near the needle, either shutter or needle being 
replaced by a reset device, which may be mechan¬ 
ical or electrical. 

Annunciator drops are made in a variety of 
forms. Fig. 52 illustrates the principle under¬ 
lying nearly all of them. 

When current hows through the magnet coils 
M, the armature A is attracted, and being pivoted 
at P } the lever hook H rises and allows the 


L.ofC. 

























































I 


56 ELECTRIC BELLS AND ALARMS 

weighted shutter S' to fall and display a number 
painted on its inside surface. 

The needle drop in Fig. 53 is one that has met 
with great favor and works as follows: the soft 
iron core of the magnet C has a hole drilled 
through it, in which turns the shaft vS\ An arrow 
or needle is attached at the front end over the 






Fig. 54 


face of the annunciator. A notched arm B is 
fixed on the rear end of the shaft and is held in 
a horizontal position by the end of armature A. 

When the current flows around C, armature A 
turns on its pivot towards the core of C, as in 
Fig. 54, unlocking B , which falls and thereby 
partly rotates shaft 5* and the arrow. 

When it is desired to reset the arrow and arm. 



















ANNUNCIATORS 


57 


a button is pressed upwards, which raises a rod 
carrying an arm R. This latter arm in turn 
raises B to its former position, the heavy end 
of A falls, and its pointed end locks B. 

Pendulum, or swinging, signals are used in an¬ 
nunciator work, where there is a liability that the 



2 ] 

Fig. 55 


ordinary drop shutter would not be reset. They, 
however, only give a visible signal for a few sec¬ 
onds, and are therefore liable to be overlooked. 

In Fig. 55 a pivoted arm carrying a soft iron 
armature A and a thin plate B having a number 
on it is free to swing in front of an electromag¬ 
net M. 











ELECTRIC BELLS AND ALARMS 


5 $ 


When the current flows in the electromagnet 
the armature is attracted, and upon the circuit 
being broken at the push, the armature is released 
and the arm swings to and fro. 

The drops of an annunciator are wired up as 
in Fig. 56. 

One end of each coil is attached to a common 



return wire C, the other end going to the push P. 
When P is depressed, the circuit of any drop is 
through M along C through bell, battery and up 
common battery wire W back to other contact 
of push P. Depressing any push does not there¬ 
fore affect any other drop but the one controlled 
by it. 
































ANNUNCIATORS 


50 


Wiring up an Annunciator. A cl 13 .gr 3 .rn of 
the connections for 311 3nnunci3tor with 3 sep 3 r 3 te 
bell is given in Fig. 57. Where the bell is con- 
t3ined in the C3se 3 terminal will be generally 
found for connection. 


The figure shows 3 wire running from the bat- 
tery to one side of e3ch push button. This is the 
common return, or battery wire, and S3ves instal- 



Fig. 57 


ling two wires from esch push. It should be 
l3rger, however, than the rest of the wires, gener- 
3lly 3bout No. 16 B. & S. 

All the wires for 311 annunciator should be run 
before connecting up. There 3i*e different methods 
of sorting out the wires 3t the 3nnunci3tor. One 
W 3 y is to connect the wires (except of course 
common or battery return wires) to the drops in 
3iiy order. Then 311 3ssist3nt travels from push 
to push 3nd presses e3ch button, noting the 
























































60 


ELECTRIC BELLS AND ALARMS 


room numbers and the order in which they were 
visited. 

As each drop falls, its number and order is 
noted. 

Comparing this with the list made by the assis¬ 
tant will show the correct changes to make. 




Fig. 58 



For instance, suppose pushes 1, 2, 3, 4, 5 and 6 
were pressed in that order, and drops 3, 4, 5, 1, 
2 and 6 fell in that order. Then the wires at 
the annunciator would be changed as follows: 
From 3 to 1, 4 to 2, 5 to 3, 1 to 4, and 2 to 5; 
6 would already be in its right place. 

Another way is to commence by twisting to- 






























































































ANNUNCIATORS 


61 


gether say the wires at No. 1 push. Then go to 
the annunciator and touch each of the push wires 
to No. 1 drop until it falls. Then connect it, 
untwist the wires at No. 1, push and connect it 
up. Proceed to No. 2 and so on until all the 
pushes have been connected in turn. 

In some cases it is desired to answer back to 
the person calling, or to be able to call any person 
from the annunciator. 

A circuit like Fig. 58 answers the purpose of 
both annunciator call and return, or fire, call. 
This requires two wires from each room to the 
annunciator and a common return wire. By trac¬ 
ing out the circuit it will be seen that when a 
room push is pressed, the annunciator needle and 
bell indicate. And when one of the pushes near 
the annunciator is pressed, the corresponding 
room bell rings. The former circuit is from the 
push, along the common return wire, through 
bell and annunciator back to the push. 

The fire call is from push up line to bell through 
bell along common return and through battery to 
the push. 

The Western Electric single-wire system 
(Fig. 59) uses three-point pushes, two batteries 
and two return wires. Battery A is for the annun¬ 
ciator circuit and battery F for the fire, or return, 
call. 


62 


ELECTRIC BELLS AND ALARMS 


Qp gV 


zf 



Cl) 





p 



4 


r 






Fig. 59 



















































































































ANNUNCIATORS 


63 


In each room the top contact and push spring 
contact are normally together. 

If one of the pushes below the annunciator is 
pressed, battery F is thrown in series with the 
bell in the room. 

But when the room push is pressed its bell is 
cut out and the circuit becomes like an ordinary 
annunciator circuit. 



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little touched upon in other works. The selection of tables will be 
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Electric Current, Insulators, Conductors, Series and Multiple 
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Motors, Management, Equalizers, Starting boxes, Sparking and 
Heating Brushes, Practical Hints, etc.; 3. Electrical Measuring 
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management, Testing, Equipments, Fluids, various Switchboards 
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Insulite ; Leclanche ; Lime Chromate ; Silver Chloride ; Smee ; Thermo¬ 
electric. i?t7/y —Annunciator System ; Double System ; and Telephone; 
Making ; Magnet for ; Bobbins or Coils ; Trembling ; Single Stroke ; 
Continuous Ringing. Connections. Carbons. Coils. —Induction ; Prim¬ 
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Speed to Power ; Field-Magnets ; Pole-pieces ; Field-magnet Coils ; 
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of size to efficiency ; Methods of exciting Field-Magnets ; Magneto-Dyna¬ 
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135 PAGES. 126 ILLUSTRATIONS. 8 VO. 

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Considerable space in the new matter is given to the following . 
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Contents of Chapters. 

1 . Construction of coils; sizes of wire; winding; testing; insula¬ 
tion; general remarks; medical and spark coils. 2 . Contact breakers. 
3 . Insulation and cements. 4. Construction of condensers. 5 . Ex¬ 
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circuit cells; solutions, n. Storage or secondary batteries; construc¬ 
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XII + 270 Pages, 79 Illustrations, 5x6^ Inches. 

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INDUCTION COILS 

AND 

Coil Making. 

A Treatise on the Construction and Working of 
Shock, Medical and Spark Coils. 

By F. C. ALLSOP. 


CONTENTS. 

Induction; iron filings round poles of a magnet; magnetic whirls 
round wires carrying electric currents; electro-magnet; apparatus for 
observing the phenomena of induction, circuits of coil with both 
primary and secondary; primary shock coil; hints on the construc¬ 
tion of coils generally; determining size of primary and secondary 
windings; table of resistances of copper wire, etc.; bobbins; iron core; 
winding the primary; winding the secondary; contact-breakers; term¬ 
inals; bases for coils; putting the coil together; construction of con¬ 
densers; shock and medical coils and their connections; methods of 
regulating shock; primary shock coils; method of winding last layer; 
bath coils; sledge coils; portable coils; street coils; accessory appli¬ 
ances for, and the application of medical coils; conducting cords and 
electrodes; galvanometers and milliamperemeters; collectors; current 
reversers; rheostats; spark coils; a i-inch spark coil; sectionally- 
wound coils; a 2 -inch spark coil; a 12 -inch spark coil; App’s spark 
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A GRADUATED COLLECTION OF 


PROBLEMS IN ELECTRICITY. 

Comprising all branches of Electrical Science. 

By ROBERT WEBER, D. Sc. 

Translated from the Third French Edition. 

By E. A. O’KEEFFE, B. E., M. I. E. E. 


EXTRACT FROM PREFACE. 

“This graduated collection of problems in electricity fills a want 
I have often felt in the course of my teaching. In order the better 
to familiarize the student with the technical terms and the formulae 
employed in this branch of physics, I thought it would be useful 
to collect a considerable number of exercises, to arrange them 
carefully, and to vary as much as possible the subjects of which they 
treat. This collection allows us to illustrate the theoretical course 
by numerous examples, to exercise the intelligence of the students, 
and to imprint on their memories the laws and electrical formulae, 
the numerous applications of which tend every day to take a 
greater place in our lives.” 

The work is divied into the following divisions: Mechanics and 
heat, with 38 problems and answers; static electricity, with 153 
problems and answers; dynamic electricity, with 555 problems and 
answers. The units adopted are mechanical, magnetic, electrical, 
practical electrical, legal and heat. With 2G tables. Index and 
contents. 

XV. + 351 pages, 34 diagrams, 12mo., doth, 


$3.00 



AND 





An Elementary Treatise for the Use of 

ELECTRICAL ARTISANS AND SCIENCE TEACHERS. 

By J. A. Fleming, M. A., D. Sc., F.R. S. 

Synopsis of Contents. 

Magnetic classification of substances. Electro-magnetism. Mag¬ 
netic retentivity and coercivity. Structure of a magnet. Substance 
and energy. Physical measurements. Fundamental units. The 
Metric system. The C. G. S. system derived units. A unit mag¬ 
netic pole. Moment of a magnet, magnetic fields and magnetic 
couples. Magnetic flux. Magnetic reluctivity and reluctance. 
Magnetomotive force. Action of a magnetic field on a magnetic sub¬ 
stance. Practical measurements of magnetic flux and magnetic 
force. Electric currents and electro motive force. Production of an 
electric current. Practical forms of Voltaic cells. Standard cells. 
Thermo-electric currents. Magneto-electric currents. Measure¬ 
ment of electric currents. Construction of a tangent galvanometer. 
Definition of the practical unit of current—one ampere. Practical elec¬ 
trical unit. Ohm’s law. Faraday’s discovery of electro-magnetic 
induction. Ballistro galvanometer. Induced electric currents. 
Mutual inductance. Conductors cutting magnetic flux. Faraday’s 
disc. The direction of the induced electro-motive force. Hand 
rule curves. Steinmetz law. Electro-magnets. Lifting power of 
electro-magnets. Construction of electro-magnets for various pur¬ 
poses. Effect of heat on magnetic properties. Alternating or 
periodic currents. Inductance. Alternating current transformers. 
Transformer distribution. Construction of alternating current trans¬ 
formers. Induction coil. Electric measuring instruments. Current 
carrying capacity of wire. Alternate current instruments. The 
dynamo. Alternators. Appendix. The measurement of the Earth’s 
Horizontal magnetic field strength. 

408 pages, 135 illustrations, i2mo, cloth, $2,00 





FINSBURY TEGHNIGAL MANUALS. 


Elementary 

TELEGRAPHY AND TELEPHONY 

BY 

ARTHUR GROTGH. 


Extract from Preface. 

“This work is intended to cover the intermediate ground between 
electricity and magnetism proper and the twin subjects of tele¬ 
graphy and telephony. 

“ The elementary student does not desire to traverse the whole 
field of electricity, either the science or its application, but to 
understand such leading principles of the one as are necessary to 
a comprehension of simpler systems of the other. It has, therefore, 
been the author’s aim to treat the subjects as fully as possible 
from this point of view, and to lay a firm foundation for the 
acquisition of larger future knowledge.” 


Contents of Chapters. 

I. —Magnetism. 

II. —Terrestrial Magnetism—Magnetic Theory. 

III. —Static Electricity. 

IV. —Electrostatic Induction—Condensers. 

V. —Dynamic Electricity—The Voltaic Cell. 

VI. —Primary and Secondary Cells. 

VII. —Resistance, Current and Electromotive Force. 

VIII. —Effects of Current—Galvanometers. 

IX. —Induction. 

X. —Cross-Section—Combined Resistances. 

XI. —Joining-Up of Ceils—Universal Battery System. 

XII. —Telegraphy : Single Needle—Sounder. 

XIII. —Relays—Double-Current Working, etc. 

XIV. —Wheatstone A B C—Steljes Recorder. 

XV. —Differential Duplex. 

XVI. —Bridge Duplex. 

XVII—Submarine. 

XVIII.—The Telephone. 

XIX. —Telegraph and Telephone Lines. 

XX. —Elements of Testing. Index. 

VII+223 Pages, 238 Illustrations, 8vo, Cloth, $ 2 .00. 





A valuable book of reference. 


TELEPHONES 

THEIR 

CONSTRUCTION AND FITTING. 

A 

Practical Treatise on the Fitting-up and Maintenance of Telephones 

and the Auxiliary Apparatus. 


By F\ C. ALLSOP. 


SYNOPSIS OP' CONTENTS. 

Receivers. —Single-pole Bell: Double-pole Bell; Watch; Membrane; 
Gower; Ader; Bell pattern Ader; D’Arsonval; Hickley; Siemens; Spoon- 
shape; Double; Bollier. Transmitters. —Hughes; Microphone; Blake; 
Gower; Ader; Crossley; Johnson; Swinton; Valve Microphone; German 
P. O.; Hunnings; Berthon; Berlinger; Induction coils for; Specifications 
for; two-pencil Microphone. Switch Bells. —Batte.y; Magneto; Connec¬ 
tions; Switch Hook; Lightning Arresters. Complete Instruments. —With 
Magnetic Transmitters; With Microphone; Gower-Bell; Bell-Blake; Cross- 
ley; Ader; Johnson; Army Service; Ship Service; for Mining and Diving 
Purposes. Long Distance Telephony. Bells. — Construction of the Mag¬ 
neto Generator; Battery; Vibrating; Single Stroke; Continuous Ringing; 
Short Circuit; Differentially wound; Circular; Church Shaped. Relays. 
Switches. —Two way; three point; four point; six point; plug. Three 
drop Annunciator; Four drop Annunciator; Connecting Plugs. Switch¬ 
boards. Batteries. —Leclanche; Agglomerate block form; Six block form. 
Position of the Battery. Setting up the Battery. Inspecting a Battery. 
Recharging a Battery; four cell Battery in box. Erecting I'elephone 
Wires. —Live Wires; Insulators; Shackles; Wall Brackets; Overhead 
Wires; Paying out Wire; Draw vice; Vicing up a span; Binding Wire to 
Insulator; Pole on Roof; Humming of Wires; Prevention; Induction and 
L'-akage; to Prevent Induction; Underground Wires; Inside or Joining up 
Wires; Earth Wires and Earth Connections; Fixing the Instruments; 
< onnecting up (with numerous diagrams). Different Methods of Arrang¬ 
ing Instruments. — Twelve different arrangements. Private Exchange 
Systems.— k For Hotels; for Large Buildings; Switch-boards. Public Ex¬ 
change Systems —Western Electric Multiple; British P. O. ; French; The 
Law; The Mann; Miller’s Improvement; Bennett’s Electro-static Call Wire. 
Testing and Removing Faults. —Searching for a fault. Faults in —Trans¬ 
mitters; Receivers; Switch Bells; Batteries; Line; Locating Faults. Index, 

184 pages. 156 illustrations and folding plates. 

121110. Cloth, $1.25 











PRACTICAL CONSTRUCTION 


of 

Electric Tramways 

—BY— 

William R. Bowker, C.E., M.E., E.E, 


“ An excellent treatise on Electric Tramway Construction, with 
numerous diagrams. The author’s treatment being essentially 
practical, he at once dips into the question of laying out the per¬ 
manent way. Chapter II. is devoted to the preparation of a sub¬ 
stantial roadbed foundation, without which it is useless to expect 
reliable results. With the aid of numerous diagrams, he then 
describes the laying of the rails, plate laying, bonding, etc. As to 
the completion of roadbeds the author notes that no pavement has 
yet been discovered with so long a life as granite sets pavement 
judiciously laid. There is a good deal of useful information on 
wood pavement. Details of overhead equipment are carefully 
considered. Local faults, materials used, and testing and mainte¬ 
nance are considered.”— Page's Engineering Magazine. 

Contents of Chapters: 1. Laying out the Permanent Way; 2. 
Road bed Foundation, etc.; 3. Laying the Rails, Plate Laying, 
Bonding, etc.; 4. Completing the Road-bed; 5. Choice of Materials 
in the Laying-out of Curves for the Overhead Equipment; 6. Over¬ 
head Construction and Equipment; 7. Notes and details on 
Materials in the Construction and Equipment of Various Tramway 
Undertakings; 8. Testing and Maintenance of Electric Tramways; 
index. 

VIII. + 119 pages, 93 diagrams, 8vo. cloth. 


$2.50 



A HAND BOOK OF 


Thlectrical Jesting, 

By H. R. KEMP, C.E. 

Sixth edition, thoroughly revised and enlarged. 


Note: —In the present edition the author has not only taken advan¬ 
tage as far as possible of the many friendly suggestions which have 
been made to him for the improvement of the original work, but has 
added a considerable amount oi new matter, besides thoroughly 
revising the old.— February , /goo. 


CONTENTS OF CHAPTERS. 

i. Simple Testing. 2 . Resistance Coils. 3 . Galvanometers. 4. 
Shunts. 5 . Measurement of Galvanometer Resistance. 6 . Measure¬ 
ment of the Internal Resistance of Batteries. 7 . Measurement of 
the Electro-motive Force of Batteries. 8 . The Wheatstone Bridge. 
9 . Localization of Faults. 10 . Keys, Switches, Condensers and 
Batteries, n. Measurement of Potentials. 12 . Measurement of 
Current Strengths. 13 . Measurement of Electro-static Capacity. 
14 . The Thompson Quadrant Electrometer. 15 . Measurement of 
High P .existences. 16 . Measurement of Resistances by Potentials. 
17 . Localization of Faults by Fall of Potentials. iG. Tests, during 
the laying of a Cable. 19 . Joint-testing. 20 . Specific Measurement. 
21. Corrections for Temperature. 22 , Localization of Faults of 
High Resistance. 23 . Localization of a Disconnection Fault in a 
Cable. 24 . A Method of Localizating Earth Faults. 25 . Galvano¬ 
meter Resistance. 26 . Specifications for Manufacture of Cable.— 
Systems of Testing Cable during Manufacture. 27 . Apoendix, 
Index and Numerous Tables. 

VIII+646 pages, 238 illustrations, 8 vo. cloth, f 6 00f 





Design of Dynamos 

BY 

SILVANUS P. THOMPSON, D. Sc., B. A., F. R. S. 

EXTRACTS FROM PREFACE. 

“ The present work is purposely confined to continuous current 
generators. The calculations and data being expressed in inch 
measures; but the author has adopted throughout the decimal sub¬ 
division of the inch; small lengths being in mils, and small areas of 
cross-section in sq. mils, or, sometimes, also, in circular mils.” 

CONTENTS OF CHAPTERS. 

1. Dynamo Design as an Art. 

2 . Magnetic Data and Calculations. Causes of waste of 
Power. Coefficients of Dispersion. Calculation of Dispersion. 
Determination of exciting ampere-turns. Example of Calculation. 

3. Copper Calculations. Weight of Copper Wire. Electrical 
resistance of Copper, in cube, strip, rods, etc. Space-factors. Coil 
Windings; Ends; Insulation; Ventilating; Heating. 

4. Insulating Materials and Their Properties. A list of 
materials, including “ Armalac,” “ Vitrite,” “ Petrifite,” “ Mican- 
ite,” “ Vulcabeston,” ‘‘Stabilite,” “ Megohmite,” etc. With tables. 

5. Armature Winding Schemes. Lap Windings, Ring Wind¬ 
ings, Wave Windings, Series Ring-Windings, Winding Formulae. 
Number of circuits. Equalizing connections. Colored plates. 

6 . Estimation of Losses, Heating and Pressure-drop. Cop¬ 
per Losses, Iron Losses, Excitation Losses, Commutator Losses, 
Losses through sparking. Friction and Windage Losses. Second¬ 
ary Copper Losses. 

7. The Design of Continuous Current Dynamos. Working 
Constants and Trial Values; Flux-densities; Length of Air-gap; 
Number of Poles; Current Densities; Number of Armature Con¬ 
ductors; Number of Commutator Segments; Size of Armature 
(Steinmetz coefficient); Assignment of Losses of Energy, Cen¬ 
trifugal Forces; Calculation of Binding Wires; Other procedure in 
design. Criteria of a good design. Specific utilization of material. 

8. Examples of Dynamo Design. 

1 . Shunt-wound multipolar machine, with slotted drum arma¬ 
ture. 2. Over-compounded Multipolar traction generator, with 
slotted drum armature, with general specifications, tables, dimen¬ 
sions and drawings, fully described. 

A number of examples of generators are given in each chapter, 
fully worked out with rules, tables and data. 

VIII.X253 pages, 92 illustrations, 10 large folding plates and 4 
Three-color Plates, 8vo., cloth, $3.50. 

(Bound in Red Cloth as a companion volume to the second edition of 

Polyphase Electric Currents.) 


AUTHORIZED AHERICAN EDITION OF 


POLYPHASE 
ELECTRIC CURRENTS 

AND 

ALTERNATE-CURRENT MOTORS 

By S. P. THOMPSON, D.Sc., B.A., F.B S. 

Second and Enlarged Edition , with Twenty-four Colored Illus 

trations and Eight Folding Plates. 


Contents of Chapters. 

I. Alternating Currents in General. 

II. Polyphase Currents. 

III. Combination of Polyphase Circuits and Economy of Copper. 

IV. Polyphase Generators. 

V. Examples of Polyphase Generators. 

VI. Structure of Polyphase Motors. 

VII-VIII. Graphic Theory of Polyphase Motors. 

IX. Analytical Theory of Polyphase Motors. 

X. Examples of Modern Polyphase Motors. 

XI. Hints on Design. 

XII. Mechanical Performance of Polyphase Motors. 

XIII. Single-Phase Motors. 

XIV. Polyphase Transformers and Phase Transformation. 

XV. Measurement of Polyphase Power. 

XVI. Polyphase Equipment of Factories. 

XVII. Distribution of Polyphase Currents from Central Stations. 
XVIII. Polyphase Electric Railways. 

XIX. Properties of Rotating Magnetic Fields. 

XX. Early Development of the Polyphase Motor. 

Appendix.— I Alternate Current Calculations : the Symbolic Me¬ 
thod. II. Schedule of Polyphase Patents. Index List of Plates:— 
I. Two-phase Generator at Cbevres. II. Three phase Inductor 
Alternator. III. Two-phase Motor of Six Horse power. IV. Three- 
phase Motor of One Hundred Horse power. V. Three phase Motor 
of Twenty Horse-power. VI. Core-Disks of Three-Phase Motor. 

VII. Two phase Motor of One Thousand Horsepower. VIII. Lo¬ 
comotive of the Jungfrau Railway. 

508 Pages, 358 Illus., 8vo, Clotli, $s.eot 






MOW READY. 


996 pages, 573 illustrations, four three-color plates, 
and 32 large folding plates and scale drawings. 
Size of book, 6i x 8 J x 2b 



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PRACTICAL HANDBOOK 


ON 



With Instructions for Care and Working of the Same. 

By G. LIECKFELD, C.E, 

TRANSLATED WITH PERMISSION OF THE AUTHOR BY 

Geo. Richmond, M.E. 

TO WHICH HAS BEEN ADDED FULL DIRECTIONS FOR THE RUNNING OF 

OIL ENGINES. 


CONTENTS. 

Choosing and installing a gas engine. The construction of good 
gas engines. Examination as to workmanship. As to running. A-; 
to economy. Reliability and durability of gas engines. Cost of in¬ 
stalling a gas engine. Proper erection of a gas engine. Construc¬ 
tion of the foundation. Arrangement for gas pipes. Rubber bag 
T ocking devices. Exhaust pipes. Air pipes. Setting up gas en- 
g». es. Brakes and their use in ascertaining the power of gas en¬ 
gines. Theory of the brake. The Brauer band brake. Arrange¬ 
ment of a brake test. Explanation of the expressions “ Brakt 
Power” and “ Indicated Power.” Comparisons of the results of the 
brake test and the indicated test. Quantity of work consumed b\ 
external friction of the engine Distribution of heat in a gas engine 
Attendance on gas engines. General remarks. Gas engine oi» 
Cylinder lubricators Rules as to starting and stopping a gas engine. 
The cleaning of a gas engine. General observations and specific ex¬ 
amination for defects. Different kinds of defectives. The engine 
refuses to work. Non-starting of the engine. Too much pressure 
on the gas. Water in the exhaust pot. Difficulty in starting the en¬ 
gine. Clogged slide valve. Leaks in gas pipes. Unexpected 
stopping of engine Irregular running. Loss of power. Weak g as 
mixtures. Late ignition. Cracks in air inlet. Back filing Knock¬ 
ing and pounding inside of engine. Dangers and precautionary 
measure in handling gas engines. Examination of gas pipes Pre 
cautions when : - Opening gas valves. Removing piston from cylin¬ 
der. Examining with light openings of gas engines. Dangers in 
starting Dangers in cleaning. Safeguards for fly-wheels. Danger 
of putting on belts. Oil Kngfines. Gas engines with producer 
gas. Gasoune and oil engines The “ Hornsby-Akroyd’ oilengine. 
Failure to start. Examination of engine in detail. Vaporizer valvt 
box. Full detailed directions for the management of Oil Engines. 
Concluding remarks. 120 pages, 'llustrated. e i2mo. cloth, $1.00 






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FOURTH EDITION. 


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Symbols and the signs of operation. The equation and the un¬ 
known quantity. Positive and negative quantities. Multiplication, 
involution, exponents, negative exponents, roots, and the use of ex¬ 
ponents as logarithms. Logarithms. Tables of logarithms and 
proportional parts. Transportation of systems of logarithms. Com¬ 
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THE ENGINEERS' SKETCH-BOOK 

OF 

Mechanical Movements, Devices, Appliances, 
Contrivances and Details. 

EMPLOYED IN THE DESIGN AND CONSTRUCTION OF MACHINERY FOR EVERY 
PURPOSE CLASSIFIED AND ARRANGED FOR REFERENCE FOR THE 
USE OF ENGINEERS, DRAUGHTSMEN, MANAGERS, ME¬ 
CHANICS, INVENTORS, PATENT AGENTS AND ALL 
ENGAGED IN THE MECHANICAL ARTS. 

BY 

THOMAS WALTER BARBER, M.E. 

Third Edition , greatly enlarged a?id brought up tc date. 

335 pages, with descriptive notes and memoranda, and 2,603 
• illustrations, 8vo, cloth. Price, $4.00. 


CONTENTS. 

Accumulators. Adjusting devices. Anchoring. Anti-friction 
bearings. Apparatus tor drawing curves. Automatic cut-off. 
Balance weights. Ball and socket joints. Beam engine diagrams. 
Bearings. Bed plates, foundations. Belt gearing. Belt pulleys. 
Blowing and exhausting. Boilers, types of. Bolts, etc. Boring, 
drilling, etc. Brakes and retarding appliances. Cams, tappets and 
wipers. Carriages, cars, etc. Centres. Centrifugal force, appli« a- 
tions of. Chains, links and couplings, Chopping, slicing and minc¬ 
ing. Chucks, grips and holders. Circular and reciprocating motion 
Clutches. Compensating and balance weights. Concentrated power. 
Concentrating and separating. Condensing and cooling. Connect¬ 
ing rods and links. Contracting and expanding. Conveying mes¬ 
sages, etc. Conveying motion and movable ports Conveyors. 
Cotters, etc. Couplings. Couplings for shafting. Covers, do.>rs, 
-tc. Cranes, types of. Cranks and eccentrics. Crushing, rolling 
md disintegrating. Curves, apparatus for drawing. Cushioning* 
Cutting tools. Differential gear. Disintegrating. Doors, covers 
manholes. Drawing and rolling metals, etc. Drawing curves etc., 
apparatus for. Drilling, boring, etc. Eccentrics. Elastic wheels. 
Elliptical motion. Engines and boilers. Engines. Exhausting aup 
blowing. Expanding and contracting devices. Fastening wheels 






JY^ecljarjics Owp^j^ook 

A WORK THAT SHOULD BE IN YOUR BOOKCASE. 

The general method of treatment of each subject, is first 
the raw materials worked upon, its characteristics, variations 
and suitability; secondly, the tools used, the sharpening 
and use; thirdly, devoted to typical examples of work to be 
done, materials, and how to do similar work, etc. 

THE FOLLOWING ARE THE PRINCIPAL CONTENTS. 

Mechanical Drawing, (13 pages.) 

Mechanical Movements, (55 pages.) 

Casting and Founding in Brass and Bronze, (30 pages.) 

Forging and Finishing, ( 4 G pages.) 

Soldering in all its branches, (26 pages.) 

Sheet Metal Working, (10 pages.) 

Turning and Turning Lathes, (31 pages.) 

Carpentry, (224 pages.) 

Log Huts, Building, Etc., (8 pages.) 

Cabinet-Making, (36 pages.) Upholstery, (6 pages.) 

Carving and Fretwork, (13 pages.) 

Picture Frame Making, (4 pages.) 

Painting, Graining and Marbling, (28 pages.) 

Staining, (13 pages.) Gilding, (3 pages.) 

Polishing, (23 pages.) Varnishing, (4 pages.) 

Paper Hanging, (4 pages.) Glazing, (7 pages.) 

Plastering and White Washing, (9 pages.) 

Lighting, (8 pages.) 

Foundations and Masonry, (46 pages.) 

Roofing, (14 pages.) 

Ventilating and Warming, (13 pages.) 

Electric Bell and Bell Hanging, Gas Fitting, (8 pages.) 

Roads and Bridges, Banks, Hedges, Ditches and Drains, As¬ 
phalt Cement Floors, Water Supply and Sanitation. 

Total number of pages 702 . Total number illustrations 1,420 

Bound in substantial half-extra, - PRICE BY MAIL ONLY $ 2.50 

We have an 8 page circular giving full contents which will be sent 
free on application. 





MANUAL OF INSTRUCTION 


H ARD S OLDERING, 

HARVEY ROWELL. 


CONTENTS. 

Introduction. Utensils and Chemicals.—The flame. Lamp. Charcoal. 
Mats. Blowpipes. Wash-bottle. Binding wire. Borax. Chemicals. 

Alloys for Hard Soldering.—bpelter. Silver solder. Gold solder. 

Oxidation.—Oxidation of metals. Fluxes. Anti-oxidizers. 

Structure of Flame.—Oxidation of gases. The cone. Oxidizing flame. 
Beducing flame. 

H^at.—Transmission. Conduction. Capacity of metals. Radiation. 
Application. 

The Process.—The work table. The joint. Applying solder. Apply¬ 
ing heat. The use of the blowpipe. Making a ferrule. Joints. 
To repair a spoon. Difficulties. To repair a watch case. Hard 
soldering with a forge or hearth. Hard soldering with tongs. 

Technical Notes.—Preserving thin edges. Silversmiths’ pickle. Re- 
storing color to gold. Chromic acid. Steel springs to mend. 
Sweating metals together. Retaining work in position. Making 
joints. Applying heat. Preventing the loss of heat. Effect of 
sulphur, lead and zinc. To preserve precious stones. Annealing 
; _ and hardening. Burnt iron. To hard solder after soft solder. 

Properties of Metals. —Tables of specific gravity.' Table of tenacity 
Table of fusibility. Fusibility of alloys. 


56 Pages, 12mo, Cloth, Price, 75 Cents - 




























-AND- 

FIRE PREVENTION. 


4 HANDBOOK FOR INSURANCE SURVEYORS, 
WORKS MANAGERS, AND ALL INTERES¬ 
TED IN FIRE RISKS AND 
THEIR DIMINUTION 

BY 

HERBERT INGLE, F.I.C., F.C.S. 


HARRY INGLE, Ph.D., B.Sc. 

TECHNOLOGICAL CHEMIST. 


Contents ot Chapters. 

I. Definition of Fire Old Theories as to its Nature, Modern Views 
of Combustion—The Physical and Chemical Properties of the Atmos¬ 
phere the Chief Properties of its Constituents—Some Conditions 
Affecting the Combustion of Substances in Air, the Principle of the 
Miner s Safety Lamp. 

II Explanation of Chemical Terms. Outline of the Atomic Theory. 
Brief Explanations of the Use of Chemical Formulae and Equations. 

III. Methods of Preparations of Oxygen. Brin’s Oxygen Manufac- 
ture—Heat Measurements, the Calorimeter, Calorific Power of Sub¬ 
stances Burning in Air. 

IV. Coal Gas: Its Preparation. Purification and Composition- 
Properties of Its Chief Constituents - Reciprocity of Combustion- 
Gaseous Diffusion—Explosion of Gases—Dust Explosions. 

V. Fuel: Chemical Composition of Wood, Charcoal, Peat, Lig 
trite. Coal, Coke, Petroleum Coal Gas—Use of ‘-Atmospheric Bur 
ners ”—Producer Gas—Water Gas—Dawson Gas. 






ABC OF THE 

Steam Engine 

WITH A DESCRIPTION OF THE 

Automatic Shaft Governor. 

By J. £ LISK, M.E. 

WITH SIX LARGE SCALE DRAWINGS. 

A practical hand-book for Firemen Helpers and Young Engineers, 
giving a set of detail drawings all numbered and lettered and with 
names and particulars of all parts of an up-to-date American High 
Speed Steam Engine. Also a large drawing and full description of 
the Automatic Shaft Governor. With notes and practical hints. 

This work will prove of great help to all young men who wish 
to obtain their Engineer’s License because it is 

Easy to Understand, Easy to Remember, 

and gives the Latest American Practice. 

I. Longitudinal Section Through Cylinder, and Top View of High Speed Hori¬ 
zontal Steam Engine. 

II. Side Elevation of High Speed Horizontal Steam Engine. 

III. Detail Drawing of Connecting Rod and Piston of High Speed Horizontal 
Steam Engine. 

IV. Detail of Piston Valve; Eccentric Strap and Rod, Valve Stem Guide; 
and Eccentric of High Speed Horizontal Steam Engine. 

V. Detail of Crosshead; Crosshead Slipper; Wrist Pin; Crank Pin; Stuffing 
Box, etc., of High Speed Horizontal Steam Engine, 

VI. Detail of Centrifugal Automatic Governor for High Speed Horizontal 
Steam Engine. 

Copies mailed, post-paid, to any address on receipt of Fifty Cents. 


Diagram of the Corliss Engine. 

A large engraving giving a Longitudinal Section of the Corliss 
Engine Cylinder, showing relative positions of the Piston, Steam 
Valves, Exhaust Valves and Wrist Plates when cut-off takes place 
at \ stroke for each 15 degrees of the circle. With full particulars. 
Reach-rods and Rock.shafts. The Circle explained. Wrist -plates 
and Eccentrics. Explanation of Figures, etc., etc. Printed on 
heavy ledger paper, size 13 in. x 19 in. Price. 25 Cents each 

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HOW TO RUN 

ENGINES AND BOILERS. 

New Edition With a Section on Water Tube Boilers. 
Practical Instruction for Young Engineers and Steam Users. 

By EGBERT POMEROY WATSON. 

Synopsis of Contents. 

Cleaning the boiler, removing scale, scale preventers, oil in boilers, 
braces and stays, mud drums and feed pipes, boiler fittings, grate 
bars and tubes, bridge walls, the slide valve, throttling engine, the 
piston, testing the slide valve with relation to the poits, defects of 
the slide valve, lap and lead, the pressure on a slide valve, stem 
connections to the valve, valves off their seats, valve stem guides, 
governors, running with the sun, eccentrics and connections, the 
crank pin, brass boxes, bearings on pins, adjustment of Dearings, 
the valve and geariDg, setting eccentrics, the actual operation, 
return crank motion, pounding, the connections, lining up engines, 
making joints, condensing engines, Torricelli’s vacuum, proof of 
atmospheric pressure, pumps, no power in a vacuum, supporting a 
water column bv the atmosphere, starting a new plant, &c., &c. 

Water tube boilers, fire tube boilers, why water tube boilers steam 
rapidly, torpedo boat boilers, management of water tube boilers, 
economy and maintenance of water tube boilers, different types of 
water tube boilers. 160 pages, illustrated, 12mo, clotf*, $1.00. 


THE FIREMAN’S GUIDE. 

/ Handbook on the Care and Management o T Boilers. 

By KARL P. DAHLSTROM, M.E. 

Contents of Chapters. 

I. Firing and Economy of Fuel,— Precautions before and 

after starting the fire, care of the fire, proper firing, draft, smoke, 
progress of firing, fuel on the grate, cleaning out. cleaning grate 
bars and ash pan, dampers, firing into two or more furnaces, dry 
fuel, loss of heat. 

II, Feed and Water Line.— Feeding, the water line, false 
water line, defective feeding apparatus, formation of scale, guage 
cocks, glass guage. the float, safety plug, alarm whistle. 

I1L Low Water and Foaming or Priming.— Precautions 
when water is low, foaming, priming. 

IV. Steam Pressure.— Steam gauge, safety valves. 

V. Cleaning and Blowing Out. —Cleaning the boiler, to 
examine the state of the boiler, blowing out, refilling the boiler. 

VI. General Di rections, —How to prevent accidents, repairs, 
the care of the boiler when not in use, testing boilers, trimming and 
cleaning outside. Summary of rules. Index, gyp, cloth- ^0 cents.' 



AN ELEMENTARY TEXT-BOOK 

ON 

STEAM ENGINES AND BOILERS, 

FOR THE 

USE OF STUDENTS IN SCHOOLS AND COLLEGES. 

BY 

J. H. KINEALY. 

Professor of Mechanical Engineering , Washington University. 


Illustrated with Diagrams and Numerous Cuts, Showing American Types 

and Details of Engines and Boilers. 


This book is written solely as an elementary text-book for the use of be¬ 
ginners and students in engineering, but more specially for the students id 
the various universities and colleges in this country. 

No attempt has been made to tell everything about any one particular 
subject, hut the author has endeavored to give the student an idea of 
elementary thermodynamics, of the action o± the steam in the cylinder of 
the engine, of the motion of the steam valve, of the differences between the 
various types of engines and boilers, of the generation of heat by combus¬ 
tion, and the conversion of water into steam. 

Care has been taken not to touch upon the design and proportion of the 
various parts of engines and boilers for strength ; as, in the opinion of ihe 
writer, that should come after a general knowledge of the engine and 
boiler has been obtained. 

In the derivation of some of the formalae in thermodynamics, it has been 
necessary to u^e the calculus, but the u>e of all mathematics higher than 
algebra and geometry has been avoided as much as possible. 

An earnest endeavor has been made to present the subject in a clear 
and concise manner, using as few words as possible and avoiding all 

padding. 

Contents of Chapters. 

Chapter I.—Thermodynamics; First Law of Thermodynamics ; Work, 
Power ; Unit of Heat; Mechanical Equivalent ; Application of Heat to 
bodies ; Second Law of Thermodynamics ; Specific Heat; Absolute Tem¬ 
perature ; Application of Heat to a Perfect Gas ; Isothermal Expansion ; 
Adiabatic Expansion ; Fusion ; Vaporisation ; Application of Heat to 
Water; Superheated Steam. Chapter II.—Theoretical Heat Engine; 
Cycle ; Thermodynamic Efficiency ; Perfect Gas Engine ; Perfect Steam 
Engine ; Theoretical Diagram of the Real Engine ; Clearance ; Efficiency 





The Slide Valve 

SIMPLY EXPLAINED. 

By W.J. TENNANT, Asso. M. Inst. Mech. E. 

The work has been thoroughly revised and enlarged 
in accordance with the present American Practice. 

By J. H. KINEALY, D. E., M. Am. Soc. Mech. E. 


The work is based upon notes and diagrams which were prepared 
by Mr. Tennant in his lectures to his classes of working engineers 
and students towards the obtainment of clear general notions upon 
the Slide Valve, its design, varieties, adjustments and management. 
They have been revised and considerably added to and in this form 
the authors believe they will be of considerable value to all 
engineers and others interested in steam engines. 


CONTENTS OF CHAPTERS. 

I. The Simple Slide. 

II. The Eccentric a Crank. Special Model to give Quantitative 

Results. 

III. Advance of the Eccentric. 

IV. Dead Centre. Order of Cranks. Cushioning and Lead. 

V. Expansion—Inside and Outside Lap and Lead; Advance 

affected thereby. Compression. 

VI. Double-ported and Piston Valves. 

VII. The Effect of Alterations to Valve and Eccentric. 

VIII. Note on Link Motions. 

IX. Note on very early cut-off, and on Reversing Gears in 

general. 

The illustrations aim to cover the different kinds of Slide Valves, 
and the circular diagrams will prove a novel feature. 

**8 Pages. 41 Illustrations 12uio. Cloth, $1.00 




THEORETICAL AND PRACTICAL 


Ammonia Refrigeration. 

A Work of Reference Jor Engineers and others Employed m the Manage • 
ment of Ice and Refrigeralio?t Machinery. 

BY ILTYD I. REDWOOD, 

Assoc. Mem. Am. Soc. of M. E.; Mem. Soc. Chem. Indus. En%. 


CONTENTS. 

B. T. U. Mechanical Equivalent of a Unit of Heat. Specific Heat. Effect of Pres¬ 
sure on Specific Heat of Ammonia Gas. Specific Heat of Air with Constant Pressure. 
Specific Heat of Air with Constant Volume. I.atent Heat. Latent Heat of Liquefaction. 
Latent Heat of Vaporizaiion. Latent Heat of Water. Absolute pressure. Absolute 
Temperature. Absolute Zero. Effect of Pressure on Volume of Gases. Theory of Re¬ 
frigeration. Freezing by Compressed Air. Freezing by Ammonia. Characteristics of 
Ammonia. Explosiveness. Tendency of the Gas to Rise. Solubility in Water. Action 
on Copper. 26° Ammonia. Anhydrous Ammonia. The Compressor. Stuffing-Boxes. 
Special Lubrication. Oil for Lubrication. Clearance Space, etc. Suction and Discharge 
Valves. Effect of Excessive Valve-Lift. Regulation of Valve-Lift. Separator, Conden¬ 
ser, Condenser-Worm, Receiver. Refrigerator or Brine Tank. Size of Pipe and Area of 
Cooling Surface. Expansion Valves. Working Details—Charging the Plant with Ammo¬ 
nia. Jacket-Water for Compressor. Jacket-Water for Separator. Quantity of Condens¬ 
ing Water Necessary. Loss due to Heating of Condensed Ammonia. Superheating Am¬ 
monia Gas. Cause of Variation in Excess Pressure. Use of Condensing Pressure in De¬ 
termining Loss of Ammonia by Leakage. Cooling Directly by Ammonia. Brine. Freez¬ 
ing Point of Brine. Effect of Composition on Freezing Point. Effect of Strength on 
Freezing Point.** Suitableness of the Brine. Making Brine. Specific Heat of Brine. 
Regulation of Brine Temperature. Indirect Effect of Condensing Water on Brine Tem¬ 
perature. Directions for Determining Refrigerating Efficiency. Equivalent of a Ton of 
Ice. Compressor Measurement of Ammonia Circulated. Loss of Weli-Jacketed Com¬ 
pressors. Loss in Double Acting Compressors. Distribution of Mercury Wells. Exam- 
1 nation of Working Parts. Indicator Diagrams. Ammonia Figures—Effectual Displace¬ 
ment? Volume of Gas. Ammonia Circulated per Twenty-Four Hours. Refrigerating 
Efficiency. Brine Figures—Gallons Circulated. Pounds Circulated. Degrees Cooled. 
Total Degrees Extracted. Loss due to Heating of Ammonia Gas. Loss due to Heating 
of Liquid Ammonia. Calculation of the Maximum Capacity of a Machine. Preparation 
of Anhydrous Ammonia. Construction of Apparatus. Condenser-Worm. Why Still is 
Worked under Pressure. Best Test for Ammonia. Water from Separators. Lime for 
Dehydrator. Yield of Anhydrous from 26° Ammonia. Index. 

150 Pages, 15 Illustrations and 24 Pages of Tables, 

l 2 mo, Cloth, $1.00. 











LUBRICANTS, 


OILS AND GREASES. 

TREATED THEORETICALLY AND GIVING PRACTICAL 
INFORMATION REGARDING THEIR 

COMPOSITION, USES AND MANUFACTURE. 

A PRACTICAL GUIDE FOR MANUFACTURERS , ENGINEERS, 

AND USERS IN GENERAL OF LUBRICANTS. 

By ILTYD I. REDWOOD, 

Associate Member American Society of Mechanical Engineers; Member Society Chemical 
Industries (England); Author of ‘Theoretical and Piactical Ammonia Refrigeration,’ 
and a ‘Practical Treatise on Mineral Uilsand Their By-Prodrcts.’ 


CONTENTS. 

Introduction. —Lubricants. 

THEORETICAL. 

Chapter I.—Mineral Oils : American and Russian ; Hydrocarbons. 

Chapter II.—Fatty Oils : Glycerides ; Vegetable Oils ; Fish Oils. 

Chapter III.—Mineral Lubricants: Graphite ; Plumbago. 

Chapter IV.—Greases : Compounded ; “ Set ” or Axle ; “ Boiled ” 
or Cup. 

Chapter V. — Tests of Oils: Mineral Oils. Tests of Oils: Fatty Oils 

MANUFACTURE. 

Chapter VI.—Mineral Oil Lubricants : Compounded Oils ; De- 
bloomed Oils. 

Chapter VII.—Greases: Compounded Greases; “Set” or Axle 
Greases ; Boiled Greases ; Engine Greases. 

Appendix. —The Action of Oils on Various Metals. Index. 

Tables: I—Viscosity and Specific Gravity. II.—Atomic Weights. 
III.—Origin, Tests, Etc of Oils. IV. —Action of Oils on Metals. > 

List of Plates : I —I. I. Redwood’s Improved Set Measuring 
Apparatus II.—Section Grease Kettle. III.—Diagram of Action 
of Oils on Metals. 

8vo. Cloth, $1.50. 




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NEW YORK, U. S. A. 


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